1. Field of the Invention
This invention relates to a circuit wiring board having a required circuit wiring pattern on an insulating base material that has widely been employed in a variety of electronic devices and apparatii. More particularly, the present invention relates to a method of forming a circuit wiring pattern. Further particularly, it relates to a method of forming a circuit wiring pattern which cannot be formed by formation steps according to the prior art such as etching or plating.
2. Description of the Related Art
Methods of forming a circuit wiring pattern on a circuit wiring board according to the prior art include a method shown in FIGS. 5A and 5B of the accompanying drawings. First of all, a resist layer 24 having a required circuit wiring pattern shape is formed on a surface of a copper foil 22 of a copper-coated laminate plate 23 comprising an insulating base material 21 and the copper foil 22 as the principal constituent members, by ordinary photo-fabrication, as shown in FIG. 5A. Next, the exposed portions are removed by etching as shown in FIG. 5B, and a circuit wiring pattern 25 is formed by peeling and removing the resist layer 24. This method is generally referred to as the subtractive process.
Another method according to the prior art is shown in FIGS. 6A and 6B. A plating resist pattern 27 is first formed at portions other than a circuit wiring pattern formation portion on an insulating base material 26 not equipped with a copper foil but having an adhesive, as shown in FIG. 6A. A conductor 28 having a required thickness is then deposited on only the circuit wiring pattern portion by means such as electroless plating or electrolytic plating as shown in FIG. 6B. Thereafter, the plating resist 27 is removed. This is a so-called additive process.
When a surface treatment layer of gold, nickel, etc, is required on the surface of the circuit wiring pattern in the prior art methods described above, a film is formed by plating.
The prior art methods described above cannot form a circuit wiring pattern having a film of titanium, ceramics, amorphous metal layers, etc, that cannot be formed by plating, on the surface of the circuit wiring pattern. These methods cannot form, either, a circuit wiring pattern comprising a material which cannot be plated or etched.